The present invention generally relates to agricultural bag unloading machines. It more particularly relates to a machine that is capable of removing agricultural material from an elongate storage bag, while its progression further into the bag is automatically controlled according to the level of resistance imposed by material remaining in the bag.
Today, animal feed and other agricultural materials are often stored in long, tubular storage bags that rest on the ground, rather than in traditional vertical silos and bunkers. Because of the volume of material that they hold when filled, these storage bags can become tremendously heavy and difficult to lift or otherwise move. Therefore, their contents must be removed while they sit in place. Once removed, the contents are usually deposited into a carrier and hauled to another location where the agricultural material may be needed.
In order to facilitate the emptying of these agricultural bags, unloading machines of various constructs have been developed in the prior art. These machines typically have a frame assembly that features a mechanism(s) for engaging material within the bag and removing it from the bag while the machine advances along the length of the stationary bag. Examples of such machines are disclosed in U.S. Pat. No. 6,109,552 to Strankman and U.S. Pat. No. 4,420,119 to Johnson.
Of course, as all agricultural storage bags are not identical, neither is the texture and density of the various agricultural materials that these bags may hold. Consequently, the ideal rate at which an unloading machine should progress further within a bag so as to avoid becoming overloaded, or “jammed,” with material that it is attempting to collect and remove depends upon the rate at which the bag is actually being emptied. However, one can appreciate that using the same unloading machine to unload identical bags containing different materials may render different emptying rates because of differences in characteristics of the bags' contents. Moreover, variations in the diameters of agricultural bags even further impact emptying rates, and the removal capacities of different machines obviously can vary.
While machines adapted specifically for unloading heavy agricultural storage bags are well-known in the prior art, the proposition of controlling the drive mechanisms of those machines in accordance with material unloading factors experienced during an actual unloading session is not. For example, it may be appropriate to intermittently start and stop a machine from advancing against material or to otherwise modify travel speed in order for a machine to maximize its unloading rate without becoming overloaded.
Therefore, it can be appreciated that there remains a need for a bag unloading machine that is capable of sensing the rate at which material is being removed from a bag, by virtue of sensing resistance forces imposed against the advancing machine by material remaining in the bag, and then modifying its further advancement into the bag in accordance with that sensed resistance to advancement so as to avoid overloading or jamming the machine's collection mechanism with material. The automatic unloading apparatus of the present invention substantially fulfills this outstanding need.